Rotisserie ovens typically utilize a single BTU input gas burner or heater means that is cycled between "on" and "off" positions in order to maintain the temperature of the cooking chamber at a predetermined level. Such cycling of the burner or heater means provides for the burner to be turned "off" when the temperature of the cooking chamber reaches a predetermined level and the burner to be turned "on" by re-ignition thereof when the temperature of the cooking chamber drops below that predetermined level
One problem which the present inventors have associated with the use of the burner to control oven temperature during the baking or cooking of the food product is the generation of undesirable levels of carbon monoxide upon each re-ignition of the burner. It is known that carbon monoxide together with high moisture content causes the surface of certain food products, such as chicken, to become a highly undesirable "pink" color. Although a "pink" colored chicken may be fully cooked, its appearance is quite unappealing and could erroneously suggest to a potential consumer that the product is undercooked. This discoloration of food products is more prominent during early baking or cooking stages, since the food product has not developed a firm outer coating or shell which diminishes the penetration of carbon monoxide through the skin of the chicken and into the meat. It is the penetration of carbon monoxide within the food product that causes it to appear "pink" in color.
Control devices used to automatically cook food products within ovens are well known. Examples of such control devices are provided in U.S. Pat. No. 4,782,445 to Pasquini, which issued on Nov. 1, 1988; U.S. Pat. No. 4,968,515 to Burkett, et al., which issued on Nov. 6, 1990; and U.S. Pat. No. 5,044,262 to Burkett et al., which issued on Sep. 3, 1991.
The present inventors are not aware of any control devices for use with rotisserie ovens which are capable of protecting food products from discoloration due to carbon monoxide penetration through the skin and into the meat of the chicken during the baking or cooking stages, particularly the very early baking stages.
Conventional rotisserie ovens typically use a single low BTU input gas burner which has the disadvantage of creating a condition whereby there is inadequate energy early in the cooking process to recover the predetermined temperature level in the oven and, thus, browning of the product is under-developed. Also, at the end of the cooking process there could be too much energy and the food product can be burned or excessively darkened.
Another disadvantage with conventional rotisserie ovens is that they rotate food products during baking or cooking at a constant speed. Operating a planetary system disposed within a rotisserie oven at a constant rotational speed causes juices from within the food products to adhere to their outer surface, whereby localized surface cooling or light stripes are formed around the outer surfaces of the food products. These light stripes may affect the degree to which the food product is cooked due to the higher levels of moisture in those areas and also has a dramatic impact on the appearance of the food product to the consumer.
The present inventors have developed a unique rotisserie oven and operating protocol which avoids cooked food products having "pink" color, light stripes or burned or darkened appearance. The present inventors have accomplished this by providing a means for controlling the rotisserie oven, wherein the temperature of the cooking chamber during the baking or cooking stages is maintained by periodically venting the excess energy and atmosphere contained within the cooking chamber without the need to cycle the burner or heater by constantly re-igniting the burner during the baking or cooking stages. The elimination of burner cycling during the baking or cooking stages minimizes the production of carbon monoxide, thereby avoiding the production of "pink" chicken meat or the like.
The present inventors have also discovered that burnt or darkened food products can be avoided during the baking or cooking stages if the oven includes both high and low BTU burner input. The present inventors have discovered that high BTU input can be utilized to recover energy lost during the process when cold product is loaded into the oven with the door open. The food product (e.g., chicken) can tolerate high BTU input during the early stages due to the color of the food and relatively low temperature. The operating controller can be programmed to shift to low BTU input to brown the food product rather than burn it and to raise the internal meat temperature concurrently. The burner ignition process is always accomplished on high BTU input followed by either a continuation of high BTU input or low BTU input as predetermined by the preprogrammed computer control.
The present invention also provides for adjustable rotational speeds for the planetary assembly, thereby avoiding localized surface cooling and light stripes at the surface of the food product.